1,720,974 research outputs found
Accounting for quality in data integration systems: a completeness-aware integration approach
Full text linkEnsuring the quality of integrated data is undoubtedly one of the main problems of integrated data systems. When focusing on multi-national and historical data integration systems, where the “space” and “time” dimensions play a relevant role, it is very much important to build the integration layer in such a way that the final user accesses a layer that is “by design” as much complete as possible. In this paper, we propose a method for accessing data in multipurpose data infrastructures, like data integration systems, which has the properties of (i) relieving the final user from the need to access single data sources while, at the same time, (ii) ensuring to maximize the amount of the information available for the user at the integration layer. Our approach is based on a completeness-aware integration approach which allows the user to have ready available all the maximum information that can get out of the integrated data system without having to carry out the preliminary data quality analysis on each of the databases included in the system. Our proposal of providing data quality information at the integrated level extends then the functions of the individual data sources, opening the data infrastructure to additional uses. This may be a first step to move from data infrastructures towards knowledge infrastructures. A case study on the research infrastructure for the science and innovation studies shows the usefulness of the proposed approach
Performance evaluation of public services with nonparametric frontiers
No full textThis doctoral thesis addresses the topic of performance evaluation of public services. The main research enquiry addressed in this thesis is: "How can we use the results of nonparametric frontier analysis of public services to help policy makers make data-driven decisions?". This question will be addressed by analysing three public services: university research and educational services, waste collection service and electricity and natural gas supply services. To answer this question, innovative state-of-the-art nonparametric frontier techniques will be applied, original databases created by integrating different sources will be used and decision support frameworks will be proposed and used in a policy data-driven perspective
A heuristic approach based on Leiden rankings to identify outliers: evidence from Italian universities in the european landscape
Full text linkWe propose an innovative use of the Leiden Rankings (LR) in institutional management. Although LR only consider research output of major universities reported in Web of Science (WOS) and share the limitations of other existing rankings, we show that they can be used as a base of a heuristic approach to identify “outlying” institutions that perform significantly below or above expectations. Our approach is a non-rigorous intuitive method (“heuristic”) because is affected by all the biases due to the technical choices and incompleteness that affect the LR but offers the possibility to discover interesting findings to be systematically verified later. We propose to use LR as a departure base on which to apply statistical analysis and network mapping to identify “outlier” institutions to be analyzed in detail as case studies. Outliers can inform and guide science policies about alternative options. Analyzing the publications of the Politecnico di Bari in more detail, we observe that “small teams” led by young and promising scholars can push the performance of a university up to the top of the LR. As argued by Moed (Applied evaluative informetrics. Springer International Publishing, Berlin, 2017a), supporting “emerging teams”, can provide an alternative to research support policies, adopted to encourage virtuous behaviours and best practices in research. The results obtained by this heuristic approach need further verification and systematic analysis but may stimulate further studies and insights on the topics of university rankings policy, institutional management, dynamics of teams, good research practice and alternative funding methods
Flexible Techniques to Detect Typical Hidden Errors in Large Longitudinal Datasets
Full text linkThe increasing availability of longitudinal data (repeated numerical observations of the same units at different times) requires the development of flexible techniques to automatically detect errors in such data. Besides standard types of errors, which can be treated with generic error correction techniques, large longitudinal datasets may present specific problems not easily traceable by the generic techniques. In particular, after applying those generic techniques, time series in the data may contain trends, natural fluctuations and possible surviving errors. To study the data evolution, one main issue is distinguishing those elusive errors from the rest, which should be kept as they are and not flattened or altered. This work responds to this need by identifying some types of elusive errors and by proposing a statistical-mathematical approach to capture their complexity that can be applied after the above generic techniques. The proposed approach is based on a system of indicators and works at the formal level by studying the differences between consecutive values of data series and the symmetries and asymmetries of these differences. It operates regardless of the specific meaning of the data and is thus applicable in a variety of contexts. We implement this approach in a relevant database of European Higher Education institutions (ETER) by analyzing two key variables: "Total academic staff" and "Total number of enrolled students", which are two of the most important variables, often used in empirical analysis as a proxy for size, and are considered by policymakers at the European level. The results are very promising
Conical Free Disposal Hull estimators of directional distances and Luenberger productivity indices for general technologies
No full textDirectional distances are a popular tool in productivity and efficiency analysis due to their versatility in evaluating the distance of Decision Making Units (DMU) to the efficient frontier of the production set. The theoretical and statistical properties of these measures are well-established in various contexts. However, the measurement of directional distances to the cone spanned by the attainable set has not yet been explored. This cone is necessary to define the Luenberger indices for general technologies. This paper aims to fill this gap by presenting a method for defining and estimating directional distances to this cone, applicable to general technologies without imposing convexity. We also discuss the statistical properties of these measures, enabling us to measure distances to non-convex attainable sets under Constant Returns to Scale (CRS), as well as measure and estimate Luenberger productivity indices and their decompositions for general technologies. In addition, we provide a detailed description of how to make inferences on these indices. Finally, we offer simulated data and a practical example of inference on Luenberger productivity indices and their decompositions using a well-known real data set
Impact of a regulatory target and external factors on the waste efficiency of Italian municipalities
Full text linkDue to increasing consumption and urbanisation, urban waste management and recycling are a primary concern in Italy. Italian waste collection underwent significant reform with the introduction of a sorted collection target of 65% of total collected waste in Legislative Decree No. 152/2006. In this article, we analyse the effect of this regulatory target on the efficiency of waste collection in 275 Italian municipalities in the years 2016-2019. We estimate the coefficients of the cost efficiencies of the sorted and unsorted waste without assuming functional forms for the efficient frontier or the distribution of efficiency. Our findings suggest that municipalities that met the 65% sorted waste target demonstrated higher efficiency as costs increased, whereas those that failed to meet the target demonstrated higher inefficiency as costs increased. Strong effects emerged for population and urban economic development on the success of waste collection, whereas only marginal effects were observed for population density and city size. To improve the situation of municipalities that are not meeting the 65% target, we propose several policy measures, including 'neighbourhood solidarity'
Viable eco-efficiency targets for waste collection communities
Full text linkWaste management is crucial for advancing the circular economy, and Italy has begun to address this issue by organizing municipalities into collaborative communities of municipalities, named ATOs. In this paper, we propose a quantitative approach based on conditional efficiency analysis to estimate viable eco-efficiency targets for these waste collection communities. The proposed targets are both eco-efficient, because they reflect optimal resource allocation within the eco-efficiency framework, and viable, because they consider the unique specificities of each waste community. The methodology determines a pathway or direction for municipalities to reach the eco-efficiency frontier based on specific external factors, ensuring that each municipality is benchmarked against others with similar contexts within the same community. Our analysis focuses on 89 Italian municipalities within the ATO "Citt & agrave; metropolitana di Roma Capitale" in 2021, revealing that size and economic development significantly contributed to viable eco-efficiency within the community during this period. The proposed approach is general and flexible and can be applied to other municipalities in Italy or across Europe. It can also be extended to meso (regional) or macro (country) levels of analysis
A robust benchmarking of direct margin in Italy's energy retail markets
No full textIn the 2000s, Italy liberalized its electricity and natural gas markets, and in 2016, it separated retail activities
from other activities within these markets. Such differentiation is unique within Europe. Italy is an ideal case for
investigating which operational factors may increase profit margins among electricity and gas retailers. The
present analysis analyzes 120 retail operators in the Italian electricity and gas markets in 2020, using two models
to assess their cost and commercial efficiencies in achieving high direct margin (defined as the difference between
revenues and raw materials cost). The findings show a positive effect of size on efficiency
Driving EU sustainability: Promoting the circular economy through municipal waste efficiency
Full text linkThe need to balance ecosystems and ensure the well-being of all people underlines the urgency of closing product life cycles. In recent years, the circular economy (CE) has emerged as one of the most relevant factors in achieving the Sustainable Development Goals. This paper presents a systematic literature review (SLR) of waste management efficiency at the European level. Furthermore, it presents a standard data envelopment analysis (DEA) of 27 European countries over the period 2017–2021, focused on municipal waste. Three models (i.e., economic, technical, sustainable) are proposed to optimise the rates of municipal waste recycling and circular material use. The SLR, based on an initial set of 216 articles that was subsequently refined through double screening to 31, highlights the strategic role of the waste management, recycling and municipal solid waste triangle. The results of the DEA indicate stronger synergy between technical and sustainability dimensions than between economic and sustainability components. Moreover, they highlight fragmented performance in Europe, with distinct clusters of countries emerging as top performers in each of the three models, and the Netherlands, Slovenia, France, Italy, Germany and Sweden demonstrating superior performance for both CE outcomes and sustainable performance. Overall, the results emphasise the strategic role played by technology in facilitating an efficient circular model of municipal waste management to minimise landfilling and other environmentally detrimental practices, thereby stimulating the development of sustainable communities for optimised waste management, in line with broader sustainability objectives
A Flexible and Sustainable Analysis of Waste Efficiency at the European Level
Full text linkhis paper analyses the waste management efficiency of European Union countries using a flexible nonparametric methodology known as directional data envelopment analysis (DEA). The study evaluates performance at the macro (country) level, considering waste generated as input, landfilled and incinerated waste as bad output and recycled waste as output. The analysis incorporates the heterogeneity and specificities of each country, with respect to social and economic sustainability, establishing specific and realistic targets for each country to achieve efficiency. The research introduces a flexible and innovative method for assessing waste management efficiency and provides new empirical evidence on European waste management, considering economic and social sustainability. The results reveal a significant disparity among European countries in both waste generation and waste recycling. Countries are categorised into five groups according to their level of efficiency, and Central European nations are observed to exhibit generally better performance. A pragmatic approach, based on clear collaboration among countries, could optimise the unique waste management characteristics of individual nations to enhance the overall efficiency of the European waste management system, contributing to a circular economy and sustainable development
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